This program has been part of an overall NASA strategy to improve small compressors in turboshaft, turbofan, and turboprop engines used in rotorcraft; fixed-wing general aviation, and cruise missile aircraft. Included has been an effort to improve performance, durability, and reliability while reducing both initial and life-cycle costs of components for advanced small gas turbine engines. Of particular interest has been the potential of scaling as a means of applying advanced technologies developed for large gas turbine engines to small gas turbine engines. This contractor has provided NASA with centrifugal compressors that can be used to evaluate the effects of direct scaling, and has established a methodology for design adjustments when direct scaling is not mechanically feasible. These objectives were accomplished by the following approaches: (1) Scaling the existing high-performance centrifugal compressor of Contract NAS3-22431 from 109-lb/sec to 2-lb/sec flow size; (2) Making the necessary adjustments to the 2-lb/sec flow size compressor to make it mechanically acceptable; (3) Directly scaling the final 2-lb/sec flow size compressor to 10-lb/sec flow size; and (4) Fabricating the resulting 10-lb/sec and 2-lb/sec flow size compressors for testing in the NASA-LEWIS Compressor Facilities.